Hello,
I just started printing again, so I loaded the latest version of Cura on my PC (4.8.0) and created a couple of calibration cube gcode files with it to make sure my printer (Ender-3) was still functional. Everything printed fine, so I started preparing to move onto some more complex models.
I started slicing a model that I know will need support, but when I checked in the preview it was showing nothing there. I went through the settings and was able to get it to start generating support for the first few models.
I work in tech support for a living, so I know how this next statement sounds, but:
I didn't touch any of the settings (honest). I had just saved the gcode for a model, cleared the build plate and loaded a new model. When I sliced it, there was no indication that supports were being used. Thinking the model was large and that it might get away without needing them, I loaded one of the previous model files where it generated supports and, there's no supports.
The following is a screenshot of the model with my settings open. If there's something I'm missing, I'd appreciate it if you could tell me what it is: